A module providing elementary operations involving scalars, vectors, and matrices
over a ring or field. Vectors are represented as [a], matrices as [[a]].
(No distinction is made between row and column vectors.)
It is the caller's responsibility to ensure that the lists have the correct number of elements.

The mnemonic for many of the arithmetic operations is that the number of angle brackets
on each side indicates the dimension of the argument on that side. For example,
v <*>> m is multiplication of a vector on the left by a matrix on the right.